Preheat the oven to 350°F (175°C). Grease an 8 x 4 inch loaf pan and line it with parchment paper, leaving a small overhang on the sides to help lift the loaf out after baking.

In a large bowl, whisk together the granulated sugar, neutral oil, and applesauce until the mixture looks smooth and well emulsified.

Pour in the oat milk and vanilla extract, whisking until the mixture becomes fully combined and smooth.

Stir in the lemon juice and lemon zest. The batter will smell bright and citrusy at this stage.

Add the buckwheat flour, almond flour, baking powder, baking soda, and salt directly into the bowl. Stir gently with a spatula until a thick but smooth batter forms.

Allow the batter to rest for 2 to 3 minutes. This step helps the buckwheat flour absorb moisture and prevents a gritty texture.

Pour the batter into the prepared loaf pan and spread it evenly with a spatula.

Sprinkle the sliced almonds across the top of the batter in a single layer for a lightly crunchy topping.

Bake for 45 to 55 minutes, until the edges are golden and a toothpick inserted into the center comes out with only a few crumbs.

Let the loaf cool in the pan for 15 minutes, then carefully lift it out using the parchment paper and transfer it to a cooling rack. Allow it to cool completely before slicing.